Ah, but two every 6 hours is 4000 mg/day, and my bottle claims that's safe. When I'm anywhere near that dose, I have a > 102F fever, which means I'm in peak form to compute dosages and timings.
Of course that's over the counter. Prescription strength also exists.
I'm a fan of switching between two pain killers / fever reducers (and only one liver killer), overlapping the effective time window by a few hours, but keeping both at ~50% the recommended max daily dose (a doctor recommended this to me a few years ago).
Of course, that makes the dose schedule more complicated, getting back to the problem it is trying to solve.
I just looked at a bottle of it here. Yes, 500mg. Adult dose: 2. That's 1,000mg. Every 6 hours to a maximum of 6 per day. That's 3,000mg/day. Danger at 7,000mg/day means a therapeutic ratio of less than three--nothing like that should be OTC and it's use should be carefully considered.